Search

Your search keyword '"Fang, Hong-Hua"' showing total 24 results
Start Over Author "Fang, Hong-Hua" Search Limiters Available in Library Collection
24 results on '"Fang, Hong-Hua"'

3. Photophysics of two-dimensional perovskites -- learning from metal halide substitution

Author

Kahmann, Simon, Duim, Herman, Fang, Hong-Hua, Dyksik, Mateusz, Adjokatse, Sampson, Medina, Martha Rivera, Pitaro, Matteo, Plochocka, Paulina, and Loi, Maria A.

Subjects
Condensed Matter - Materials Science
Abstract

Whereas their photophysics exhibits an intricate interplay of carriers with the lattice, most reports have so far relied on single compound studies. With the exception of variations of the organic spacer cations, the effect of constituent substitution on the photophysics and the nature of emitting species, in particular, has remained largely under-explored. Here PEA$_2$PbBr$_4$, PEA$_2$PbI$_4$, and PEA$_2$SnI$_4$ are studied through a variety of optical spectroscopy techniques to reveal a complex set of excitonic transitions at low temperature. We attribute the emergence of weak high energy features to a vibronic progression breaking Kasha's rule and highlight that the responsible phonons cannot be accessed through simple Raman spectroscopy. Bright peaks at lower energy are due to two distinct excitons, of which the upper is a convolution of a bright exciton and a localised state, whereas the lower is attributed to shallow defects. Our study offers deeper insights into the photophysics of two-dimensional perovskites through compositional substitution and highlights critical limits to the communities' current understanding of the photophysics of these compounds.

Published
2021
Full Text
View/download PDF

4. Band-edge Exciton Fine Structure and Exciton Recombination Dynamics in Single crystals of Layered Hybrid Perovskites

Author

Fang, Hong-Hua, Yang, Jie, Adjokatse, Sampson, Kamminga, Machteld E., Duim, Herman, Ye, Jianting, Blake, Graeme R., Even, Jacky, and Loi, Maria Antonietta

Subjects
Condensed Matter - Materials Science
Abstract

Two-dimensional (2D) perovskite materials have recently re-attracted intense research interest for applications in photovoltaics and optoelectronics. As a consequence of the dielectric and quantum confinement effect, they show strongly bound and stable excitons at room temperature. In this report, the band-edge exciton fine structure and in particular its exciton and biexciton dynamics in high quality crystals of (PEA)2PbI4 are investigated. A comparison of bulk and surface exciton lifetimes yields a room temperature surface recombination velocity of 2x10^3cm/s and an intrinsic lifetime of 185ns. Biexciton emission is evidenced at room temperature, with binding energy of about 45meV and a lifetime of 80ps. At low temperature, exciton state splitting is observed, which is caused by the electron-hole exchange interaction. Transient photoluminescence resolves the low-lying dark exciton state, with a bright/dark splitting energy estimated to be 10meV. This work contributes to understand the complex scenario of the elementary photoexcitations in 2D perovskites., Comment: 15 Pages, 5 Figures and supplementary material

Published
2019

6. Unraveling the Broadband Emission in Mixed Tin-Lead Layered Perovskites

Author

Fang, Hong Hua, Tekelenburg, Eelco K., Xue, Haibo, Kahmann, Simon, Chen, Lijun, Adjokatse, Sampson, Brocks, Geert, Tao, Shuxia, Loi, Maria Antonietta, Fang, Hong Hua, Tekelenburg, Eelco K., Xue, Haibo, Kahmann, Simon, Chen, Lijun, Adjokatse, Sampson, Brocks, Geert, Tao, Shuxia, and Loi, Maria Antonietta

Abstract

Low-dimensional halide perovskites with broad emission are a hot topic for their promising application as white light sources. However, the physical origin of this broadband emission in the sub-bandgap region is still controversial. This work investigates the broad Stokes-shifted emission bands in mixed lead-tin 2D perovskite films prepared by mixing precursor solutions of phenethylammonium lead iodide (PEA2PbI4, PEA = phenethylammonium) and phenethylammonium tin iodide (PEA2SnI4). The bandgap can be tuned by the lead-tin ratio, whereas the photoluminescence is broad and significantly Stokes-shifted and appears to be fairly insensitive to the relative amount of Pb and Sn. It is experimentally observed that these low-dimensional systems show substantially less bandgap bowing than their 3D counterpart. Theoretically, this can be attributed to the smaller spin–orbit coupling effect on the 2D perovskites compared to that of 3D ones. The time-resolved photoluminescence shows an ultrafast decay in the high-energy range of the spectra that coincides with the emission range of PEA2SnI4, while the broadband emission decay is slower, up to the microsecond range. Sub-gap photoexcitation experiments exclude exciton self-trapping as the origin of the broadband emission, pointing to defects as the origin of the broadband emission in 2D Sn/Pb perovskite alloys.

Published
2023

7. Highly Fluorescent Semiconducting Two-Dimensional Conjugated Polymer Films Achieved by Side-Chain Engineering Showing Large Exciton Diffusion Length

Author

Wang, Yongshuai, primary, Zhang, Qing, additional, Li, Xiao-Ze, additional, Shu, Zhibin, additional, Zhang, Yihan, additional, Gao, Can, additional, Li, Yang, additional, Liu, Hao, additional, Li, Chenguang, additional, Fang, Hong-Hua, additional, Sun, Hong-Bo, additional, Zhang, Xiaotao, additional, Hu, Wenping, additional, and Dong, Huanli, additional

Published
2022
Full Text
View/download PDF

11. Multiband electronic transitions in 2D and 3D hybrid perovskites: recent results

Author

Even, Jacky, Tsai, Hsinhan, Nie, Wanyie, Neukirch, Amanda, Blancon, Jean-Christophe, Pedesseau, Laurent, Durand, Olivier, Traoré, Boubacar, Kepenekian, Mikael, Stoumpos, Constantinos, Tamarat, Philippe, Lounis, Brahim, Sfeir, Matthew, Fang, Hong-Hua, Shen, Qing, Loi, Maria Antonietta, Hayaze, Shuzi, Crochet, Jared, Tretiak, Sergei, Kanatzidis, Mercouri, Mohite, Aditya, Katan, Claudine, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Los Alamos National Laboratory (LANL), Rice University [Houston], Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Northwestern University [Evanston], Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Brookhaven National Laboratory [Upton, NY] (BNL), U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Zernike Institute for Advanced Materials, University of Groningen [Groningen], Department of Electronic Engineering [Tokyo], University of Electro-Communications [Tokyo] (UEC), Kyushu Institute of Technology, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE), and Kyushu Institute of Technology (Kyutech)

Subjects
[PHYS]Physics [physics], [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

12. Unravelling light-induced degradation of layered perovskite crystals and design of efficient encapsulation for improved photostability

Author

Fang, Hong Hua, Yang, Jie, Tao, S.X., Adjokatse, Sampson, Kamminga, Machteld, Ye, Jianting, Blake, Graeme, Even, Jacky, Loi, Maria, Fang, Hong Hua, Yang, Jie, Tao, S.X., Adjokatse, Sampson, Kamminga, Machteld, Ye, Jianting, Blake, Graeme, Even, Jacky, and Loi, Maria

Abstract

Layered halide perovskites have recently shown extraordinary potential for low-cost solution-processable optoelectronic applications because of their superior moisture stability over their 3D counterparts. However, few studies have investigated the effect of light on layered hybrid perovskites. Here, the mechanically exfoliated nanoflakes of the 2D perovskite (PEA) 2PbI 4 (PEA, 2-phenylethylammonium) are used as a model to investigate their intrinsic photostability. The light-induced degradation of the flakes is investigated by using in situ techniques including confocal laser scanning microscopy, wide-field fluorescence microscopy, and atomic force microscopy. Under resonant photoexcitation, (PEA) 2PbI 4 degrades to PbI 2. It is clearly shown that this process is initiated at the crystal edges and from the surface. As a consequence, the photoluminescence of (PEA) 2PbI 4 is progressively quenched by surface traps. Importantly, the light-induced degradation can be suppressed by encapsulation using hexagonal boron nitride (hBN) flakes and/or polycarbonates. This report sheds light on a specific mechanism of light-induced degradation in layered perovskites and proposes a new encapsulation method to improve their photostability.

Published
2018

13. Advances and Promises of Layered Halide Hybrid Perovskite Semiconductors

Author

Pedesseau, Laurent, Sapori, Daniel, Traoré, Boubacar, Robles, Roberto, Fang, Hong-Hua, Loi, Maria Antonietta, Tsai, Hsinhan, Nie, Wanyi, Blancon, Jean-Christophe, Neukirch, Amanda, Tretiak, Sergei, Mohite, Aditya, Katan, Claudine, Even, Jacky, Kepenekian, Mikaël, Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Zernike Institute for Advanced Materials, University of Groningen [Groningen], Rice University [Houston], Los Alamos National Laboratory (LANL), The work at FOTON was performed using HPC resources from GENCI-CINES/IDRIS Grant 2016-c2012096724. J.E.’s work is supported by the Fondation d’entreprises banque Populaire de l’Ouest under Grant PEROPHOT 2015. The work at Los Alamos National Laboratory (LANL) was supported by LANL LDRD program and was partially performed at the Center for Nonlinear Studies and at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Science user facility. The Groningen team would like to acknowledge funding by the Foundation for Fundamental Research on Matter (FOM), which is part of The Netherlands Organization for Scientific Research (NWO), under the framework of the FOM Focus Group 'Next Generation Organic Photovoltaics'. ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295)., ANR-15-CE05-0023,SuperSansPlomb,Cellule Solaire Utilisant des Pérovskites Hybrides Sans Plomb(2015), ANR-15-CE05-0018,TRANSHYPERO,Vers une compréhension des propriétés de transport électronique des cellules solaires basées sur les pérovskites hybrides(2015), ANR-12-BS10-0011,SNAP,Nano-plaquettes colloïdales atomiquement plates(2012), European Project: 687008,H2020,H2020-FETOPEN-2014-2015-RIA,GOTSolar(2016), European Project: 306983,EC:FP7:ERC,ERC-2012-StG_20111012,HYSPOD(2013), European Research Council, Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), European Commission, Los Alamos National Laboratory, Fondation Banque Populaire de l'Ouest, Department of Energy (US), Foundation for Fundamental Research on Matter, Netherlands Organization for Scientific Research, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-Télécom Bretagne, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
k-p, SOLAR-CELLS, Phase transition, Dielectric confinement, General Physics and Astronomy, 02 engineering and technology, 01 natural sciences, 7. Clean energy, quantum confinement, [SPI]Engineering Sciences [physics], LEAD IODIDE PEROVSKITE, CRYSTAL-STRUCTURE, General Materials Science, Bethe−Salpeter equation, [PHYS]Physics [physics], PHOTOVOLTAIC CELLS, ORGANIC-INORGANIC PEROVSKITES, General Engineering, OPTICAL-PROPERTIES, 021001 nanoscience & nanotechnology, layered materials, Optoelectronics, PHASE-TRANSITIONS, Density functional theory, Condensed Matter::Strongly Correlated Electrons, Hop (telecommunications), 0210 nano-technology, Rashba, k·p, Materials science, Band gap, BAND-GAP, Nanotechnology, 010402 general chemistry, EFFECTIVE MASSES, Tetragonal crystal system, Layered materials, halide perovskites, dielectric confinement, [CHIM]Chemical Sciences, Quantum confinement, Exciton, density functional theory, Perovskite (structure), exciton, business.industry, 0104 chemical sciences, Bethe-Salpeter equation, Semiconductor, Halide perovskites, Quantum dot, business
Abstract

Layered halide hybrid organic-inorganic perovskites (HOP) have been the subject of intense investigation before the rise of three-dimensional (3D) HOP and their impressive performance in solar cells. Recently, layered HOP have also been proposed as attractive alternatives for photostable solar cells and revisited for light-emitting devices. In this review, we combine classical solid-state physics concepts with simulation tools based on density functional theory to overview the main features of the optoelectronic properties of layered HOP. A detailed comparison between layered and 3D HOP is performed to highlight differences and similarities. In the same way as the cubic phase was established for 3D HOP, here we introduce the tetragonal phase with D symmetry as the reference phase for 2D monolayered HOP. It allows for detailed analysis of the spin-orbit coupling effects and structural transitions with corresponding electronic band folding. We further investigate the effects of octahedral tilting on the band gap, loss of inversion symmetry and possible Rashba effect, quantum confinement, and dielectric confinement related to the organic barrier, up to excitonic properties. Altogether, this paper aims to provide an interpretive and predictive framework for 3D and 2D layered HOP optoelectronic properties., The work at FOTON is supported by Agence Nationale pour la Recherche (SNAP and SuperSansPlomb projects) and was performed using HPC resources from GENCI-CINES/IDRIS Grant 2016-c2012096724. The work at ISCR is supported by Agence Nationale pour la Recherche (TRANSHYPERO project). J.E.’s work is supported by the Fondation d’entreprises banque Populaire de l’Ouest under Grant PEROPHOT 2015. The work at Los Alamos National Laboratory (LANL) was supported by LANL LDRD program and was partially performed at the Center for Nonlinear Studies and at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Science user facility. The Groningen team would like to acknowledge funding from European Research Council (ERC Starting Grant “Hy-SPOD” No. 306983) and by the Foundation for Fundamental Research on Matter (FOM), which is part of The Netherlands Organization for Scientific Research (NWO), under the framework of the FOM Focus Group “Next Generation Organic Photovoltaics”. ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). This project received funding from the European Union's Horizon 2020 research and innovation programme under the grant agreement no. 687008.

Published
2016
Full Text
View/download PDF

17. Benzylamine-Treated Wide-Bandgap Perovskite with High Thermal-Photostability and Photovoltaic Performance

Author

Zhou, Yang, Wang, Feng, Cao, Yu, Wang, Jian-Pu, Fang, Hong-Hua, Antonietta Loi, Maria, Zhao, Ni, Wong, Ching-Ping, Zhou, Yang, Wang, Feng, Cao, Yu, Wang, Jian-Pu, Fang, Hong-Hua, Antonietta Loi, Maria, Zhao, Ni, and Wong, Ching-Ping

Abstract

Mixed iodide-bromide organolead perovskites with a bandgap of 1.70-1.80 eV have great potential to boost the efficiency of current silicon solar cells by forming a perovskite-silicon tandem structure. Yet, the stability of the perovskites under various application conditions, and in particular combined light and heat stress, is not well studied. Here, FA(0.15)Cs(0.85)Pb(I0.73Br0.27)(3), with an optical bandgap of approximate to 1.72 eV, is used as a model system to investigate the thermal-photostability of wide-bandgap mixed halide perovskites. It is found that the concerted effect of heat and light can induce both phase segregation and decomposition in a pristine perovskite film. On the other hand, through a postdeposition film treatment with benzylamine (BA) molecules, the highly defective regions (e.g., film surface and grain boundaries) of the film can be well passivated, thus preventing the progression of decomposition or phase segregation in the film. Besides the stability improvement, the BA-modified perovskite solar cells also exhibit excellent photovoltaic performance, with the champion device reaching a power conversion efficiency of 18.1%, a stabilized power output efficiency of 17.1% and an open-circuit voltage (V-oc) of 1.24 V., Funding Agencies|Theme-based Research Scheme from the Research Grants Council of Hong Kong [T23-407/13-N]

Published
2017
Full Text
View/download PDF

18. Advances and promises of layered halide hybrid perovskite semiconductors

Author

European Research Council, Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), European Commission, Los Alamos National Laboratory, Fondation Banque Populaire de l'Ouest, Department of Energy (US), Foundation for Fundamental Research on Matter, Netherlands Organization for Scientific Research, Pedesseau, Laurent, Sapori, Daniel, Traore, Boubacar, Robles, Roberto, Fang, Hong-Hua, Loi, Maria Antonietta, Tsai, Hsinhan, Nie, Wanyi, Blancon, Jean-Christophe, Neukirch, Amanda, Tretiak, Sergei, Mohite, Ashwini A., Katan, Claudine, Even, Jacky, Kepenekian, M., European Research Council, Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), European Commission, Los Alamos National Laboratory, Fondation Banque Populaire de l'Ouest, Department of Energy (US), Foundation for Fundamental Research on Matter, Netherlands Organization for Scientific Research, Pedesseau, Laurent, Sapori, Daniel, Traore, Boubacar, Robles, Roberto, Fang, Hong-Hua, Loi, Maria Antonietta, Tsai, Hsinhan, Nie, Wanyi, Blancon, Jean-Christophe, Neukirch, Amanda, Tretiak, Sergei, Mohite, Ashwini A., Katan, Claudine, Even, Jacky, and Kepenekian, M.

Abstract

Layered halide hybrid organic-inorganic perovskites (HOP) have been the subject of intense investigation before the rise of three-dimensional (3D) HOP and their impressive performance in solar cells. Recently, layered HOP have also been proposed as attractive alternatives for photostable solar cells and revisited for light-emitting devices. In this review, we combine classical solid-state physics concepts with simulation tools based on density functional theory to overview the main features of the optoelectronic properties of layered HOP. A detailed comparison between layered and 3D HOP is performed to highlight differences and similarities. In the same way as the cubic phase was established for 3D HOP, here we introduce the tetragonal phase with D symmetry as the reference phase for 2D monolayered HOP. It allows for detailed analysis of the spin-orbit coupling effects and structural transitions with corresponding electronic band folding. We further investigate the effects of octahedral tilting on the band gap, loss of inversion symmetry and possible Rashba effect, quantum confinement, and dielectric confinement related to the organic barrier, up to excitonic properties. Altogether, this paper aims to provide an interpretive and predictive framework for 3D and 2D layered HOP optoelectronic properties.

Published
2016

23. Two-Photon Absorption and Spectral-Narrowed Light Source.

Author

Fang, Hong-Hua, Xu, Bin, Chen, Qi-Dai, Ding, Ran, Chen, Fei-Peng, Yang, Jie, Wang, Rui, Tian, Wen-Jing, Feng, Jing, Wang, Hai-Yu, and Sun, Hong-Bo

Subjects
*TWO-photon absorbing materials, *SPECTRUM analysis, *LIGHT sources, *ANTHRACENE, *ELECTRONIC excitation, *SECOND harmonic generation, *OPTICAL amplifiers, *FIELD emission, *SOLID-state lasers
Abstract

This paper reports the two-photon absorption (TPA) and the spectral-narrowed light emission (SNLE) from the crystals of 9, 10-distyrylanthracene (DSA) derivatives. The results obtained by the Z-scan method show that the tested molecules possess high TPA cross sections. Upon near-IR excitation, strong two-photon-excited fluorescence could be observed in the crystals of four types of materials. Furthermore, SNLE with low threshold occurs in three of the four crystals under pumping with the second harmonic generated in the amplifier. Single crystals of the DSA derivatives exhibit unique photonic properties, including strong solid-state fluorescence, large TPA cross section, and stimulated emission. The results demonstrate that these are potential candidates for compact and practical solid-state laser applications. [ABSTRACT FROM PUBLISHER]

Published
2010
Full Text
View/download PDF

24. Time-resolved fluorescence study of aggregation-induced emission enhancement by restriction of intramolecular charge transfer state.

Author

Gao BR, Wang HY, Hao YW, Fu LM, Fang HH, Jiang Y, Wang L, Chen QD, Xia H, Pan LY, Ma YG, and Sun HB

Abstract

Cyano-substituted oligo (alpha-phenylenevinylene)-1,4-bis(R-cyano-4-diphenylaminostyryl)-2,5-diphenylbenzene (CNDPASDB) molecules are studied in solution and aggregate state by time-resolved fluorescence techniques. CNDPASDB exhibits a strong solvent polarity dependent characteristic of aggregation-induced emission (AIE). By time-dependent spectra, the gradual transition from local excited state to intramolecular charge transfer state with the increasing solvent polarity is clearly resolved. The transition time in high polarity solvent DMF is very fast, around 0.5 ps, resulting in a low fluorescence quantum yield. While in aggregate state, the intramolecular torsion is restricted and the local environment becomes less polar. Thus, the intramolecular charge transfer state is eliminated and efficient AIE occurs.

Published
2010
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results